Power and free conveyor system



1961 P. KLAMP 2,971,474

POWER AND FREE CONVEYOR SYSTEM 3 Sheets-Sheet 1 Original Filed July 30,1956 I N VEN TOR P UL KLAMP BY 4% w W ATTORNEYS FIG.2.

Feb. 14, 1961 P. KLAMP POWER AND FREE CONVEYOR SYSTEM Original FiledJuly 30, 1956 3 Sheets-Sheet 2 INVENTOR. UL KLAM BY Q ATTORNEYS Feb. 14,1961 P. KLAMP 2,971,474

POWER AND FREE CONVEYOR SYSTEM Original Filed July so, 1956 3Sheets-Sheet 3 FIG.4.

PAU KLAMP m AT %RNEYS rates POWER AND FREE CONVEYOR SYSTEM Originalapplication July 30, 1956, Ser. No..601,001. Divided and thisapplication Dec. 3, 1956, Ser. No. 625,646

2 Claims. (Cl. 104-172) The present invention relates to improvements ina load supporting track trolley for an overhead conveyor system, inparticular a system of the power and free type such as is illustratedand described in the copending application of Leonard J. Bishop and PaulKlamp, Serial No. 513,452, filed June 6, 1955, now U.S. Letters PatentNo. 2,868,138 of January 13, 1959.

This type of conveyor is characterized by a main driving chain andtrolleys traversing an endless overhead track, with a plurality of thework supporting trolleys according to the invention traversing anendless track beneath said overhead track, and advanced by driving lugson the chain. The trolleys may be selectively diverted from a mainsupporting track reach beneath the driving chain onto and oil? a branchor free track at an angle to the main track, as disclosed in mycopending application, Serial No. 601,001, filed July 30, 1956, now U.S.Letters Patent No. 2,868,139 of January 13, 1959, of which the presentapplication is a division.

It is one object of the invention to provide a track trolley for asystem as described, in which the trolley operates through certain trackengaging, guiding and steering rollers thereof to control the operationof the switch means by which the trolley is diverted to or from thebranch track. As herein shown, the operation is one of restoring theswitch to a non-diverting position. In another installation it may bethe restoring of a previously actuated trolley control mechanism.

Another object of the invention is to provide an improved track trolleyhaving front and rear drive dogs, adapted to be engaged by advancingchain lugs, pivoted on a rugged trolley carriage which is borne by frontand rear pairs of load supporting rollers or wheels traveling on a pairof horizontal, opposed track members, and in which front and rear guideand steering rollers engage between said track members and are swiveledin an improved manner relative to the carriage and its load supportingrollers.

A further object is to provide a trolley structure of this characterfeaturing a load supporting hanger pivoted on the trolley carriage in anelevated relation to the load supporting and guide rollers of thelatter, thus to stabilize the trolley against a tendency to up-end. Theneed for trolley hold-down provisions, such as are commonly requiredwhen the trolley is being pushed up a slope, is avoided.

In accordance with this object, the load supporting hanger is pivotallysuspended on the trolley at a sufiiciently elevated point, in referenceparticularly to the load supporting rollers of the trolley, to cause theload to stabilize the trolley under the combined effect of a forcecoupleexerted thereon by a propelling chain and acting about the forward loadroller axis, as in advancing the trolley up a slope, and the load actionof the forward and rearward trolley load rollers on the track. Thiscombination of propelling and load forces occasions the upending effectreferred to if the load is hung from a point top far down on thetrolley. a

Patented Feb. 14, 1961 More specifically, the axis of suspension is solocated that the line of gravitational load action on the trolley itselfis brought between the resultants of combined components of downwardroller-on-track load action at the rollers and of the above-mentionedforce-couple action on the trolley, as at an upwardly extending dog ofthe trolley.

Yet another object is to provide an improved trolley having pairs offront and rear guiding and steering rollers which travel between and areguided by the vertical webs of opposed track channel sections, on thetop flanges of which the load supporting rollers travel, and in whichthe sets of guide rollers are journaled in depending relation to theload rollers on the horizontal axle structure of the respective frontand rear load roller pairs.

A still further object is to provide a trolley construction as set forthin the preceding paragraph in which the load roller axles are carried onupright swivels journaled respectively adjacent the front and rear ofthe trolley carriage, thereby providing a highly desirable runningaction for the trolley, insuring better steerability as the trolleytravels its track, under the control of vertically journaled front andrear guide rollers running between opposed upright webs of the track.

Another and more specific object is to provide a trolley featuringvertically journaled guide rollers, arranged in pairs at the front andrear of the trolley carriage; the extreme front and rear rollers of thefour being at a lower elevation than the two intermediate guide rollers,so as to be capable of actuating a mechanical switch reset arm, or thelike, extending through the vertical web of a trolley track section orchannel. Moreover, in the interest of increased strength, rigidity andstability, the two intermediate guide rollers are located at theelevation of the top horizontal flanges of the track section, while theload supporting rollers ride those flanges in zones directly over thevertical channel webs.

A general object is to provide a trolley affording the above recitedattributes of stability, steerability and the like which is at the sametime very simple and economical in its construction, and extremelystrong and rugged.

The foregoing as well as other objects will be made more apparent asthis description proceeds, especially when considered in connection withthe accompanying drawings, wherein:

Fig. 1 is a fragmentary view in side elevation, partially broken awayand in vertical section, showing a trolley assembly and its provisionsfor supporting and advancing the same;

Fig. 2 is a fragmentary view, partially in transverse vertical section,showing a trolley and a coacting transfer chain in relation to the maintrolley drive chain and trolley structure of the conveyor system;

Fig. 3 is a view in vertical section along line 3-3 of Fig. 1; and

Fig. 4 is a fragmentary top plan view showing the main operatingcomponents of a branch track switch mechanism controlled by the trolley,different positions thereof being generally indicated in solid anddotted line.

Figs. 2 and 4 of the drawings depict a typical setting, illustrated anddescribed in full detail in my copending application identified above,for the use of theimproved trolley of the invention, generallydesignated 1%). The

copending application of Leonard J. Bishop and Joel H.

Barlow, Serial No. 619,249, filed ()ctober 30, 1956, now U.S. LettersPatent No. 2,875,703 of March 3, 1959,

, concerns a related installation in which features of the trolley arealso put to novel use. However, it will .be

appreciated that the trolley structure is in nowise limited to theseparticular systems.

An exit switch mechanism ll controls the travel ofthe work Supportingtrolleys .10 in referenceto approach and departure sections 12, 12'respectively, of a trolley supporting track, generally designated 13,and in reference to a branch track section 14 disposed at a 90 angle tothe track 13. As indicated in Fig. 2, the track. sections areconstituted by. opposed channel sections.Sv disposed with their webportions face to face. The branch track 14 merges with main track 13,adjacent the switch mechanism It through a curved portion which isdesignated 15. The upper horizontal flanges 16 of these sections providetrack surfaces for the pairs of front and rear load supporting rollersor wheels 17 of trolleys 10, it being noted that these rollers travel onthe flanges 16 directly over the vertical webs 18 of the channels.

The structure as described is supported in an overhead position in awell known manner, as by angle iron work, generally designated 19.

Referring to Fig. 4, the reference numeral 20 designates a switch tongueof the exit switch mechanism 11, which.

tongue is, pivoted at the junction of the curved. and straight tracksections and. 12. It is.controlled, in switching trolleys onto thebranch. track 14, by. latch structure which is germane to this.invention only in the feature that the tongue 20 carries a rear resetextension arm 26''. In one position thisarm extends through an openingin the adjacent web 18 of the curved track section 15, as shown indotted line, for a purpose to be described.

Each trolley 10 includes forward and rearward sets of two guide rollers21, 21, which travel between the track section webs 18, as well as acentral depending hanger or frame 22 from which a load support 23swings. The hanger 22 is provided with a conventional bumper 23' ofrectangular outline.

Structural details of the load supporting rollers 17 and guide rollers21, 21' of the trolley, and their mount on the trolley carriage, will behereinafter set forth. In general, they serve a function of guiding thehorizontal tracking of the trolley, enabling its front and rear loadrollers 17 to be quite widely spaced from one another in the interest ofbringing the pivot point of a load supporting hanger (to be described)as high as possible on the trolley and between the load roller axes, andthus stabilizing the trolley against up-ending, as mentioned above.

The reference numeral 24 generally designates an upper, chain drivenWork advancing trolley, whose rollers 25 travel along the horizontalflanges of an elongated track I-beam 26 constituting a part of the maindrive chain track structure. A number of such forwarding trolleys areadvanced by an endless chain 27, whose links they engage atlongitudinally spaced points. As shown in Figs. 1 and 2, certain ofthese links specially designated 27, are provided for this purpose withdepending.

driving lugs 28. The trolleys 24 are connected to the chain 27 bydepending arms 29 appropriately secured to the chain. 7

As shown in Fig. 2, the chain 27 may be sustained along its side bybacking rollers 45 journaled on vertical trunnio-ns on the main tracksection 13 forwardly of the exit switch mechanism 11.

Referring now toFig. 1, theload supporting trolley 1t) is shown in itsnormal operating relation to the trolley advancing chain 27, the chainlug 28 extending downwardly between front and rear pivoted andcounterweighted trolley dogs 31, 32, respectively. The load supportingrollers 17 are mounted byball bearings 33 (Fig. 3) on tubular crossshaft or axle elements 34,

V which are fixedly carried by swivel brackets or mounts 35 ofthetrolley 10. .Upright trunnion pins36 on the mounts 35 permit theroller assembly to swivel on a I vertical axis relative to the rigid andunitary trolley carriage or frame 37, as in rounding the branch tracksection 15. 1

It will be notedby r'eference'to Fig 1, that there are two sets of thever tically.-journaled guide rollers associ- SiWith; each';trolley 18.These include the extreme forl 4 ward and rearward rollers 21, which arelocated. at a lower elevation than the intermediate guide rollers 21'and are thus positioned for engagement with the switch tongue extension20" (Fig. 4) to reset tongue 20 from the dotted to the solid lineposition once the tongue has been unlatched by the unit 20. It is to benoted that the intermediate guide rollers 21' are at the elevation of.the horizontal top track flanges 16 to avoid engagement with the tongueextension. 7

The respective sets of guide rollers 21; 21" are. carried by lateralextensions of the swivel brackets 35 of the trolley; the sets of rollersprojecting forwardly and rearwardly of the load supporting rollers 17 ofthe trolley, i.e., leading and trailing its carriage 37. The trolley isthus reversible as to its position .on the track.

As shown in Fig. 1, the load supporting hanger bar 23 is pivoted at 38on the trolley hanger 22, substantially in the horizontal plane of theset of upper guide rollers 21', and closely adjacent a plane through theaxes of the load rollers 17. Hence in swinging in a vertical plane, asindicated in solid and dotted line, and when on a slope, the load doesnot exert substantial upsetting or up-ending forces on the trolleycarirage, as it would through a rigidly connected bar or a bar lessadvantageously pivoted at a lower elevation in relation to the trolleycarriage. Hence, special hold-down means to vertically restrain thetrolley 10 are unnecessary.

It is seen by reference to Fig. 1 that with the chain 27 traveling tothe left its lug 28 exerts a force on the front trolley dog 31 involvinga couple which tends to tilt the trolley upwardly about its front trackroller 17. Due to the. relatively high pivoting of the load hanger 23 at38 between the load and guide rollers of the trolley carriage, thistendency is most effectively resisted and the trolley is mosteffectively held to the track. The lower the load is hung the morepronounced is the tilting effect.

While on a run of the trolley along a horizontal reach of the track, theupsetting or up-ending. tendency can be put up with, so long as thepivot 33 of the hanger bar 23 lies between parallel-gravitaitonal loadplanes through the load roller shafts or axes 34, and, regardless of theelevationof the pivot 38 on the carriage, the tendency becomesveryobjectionable when the trolley is being propelled by chain 27 up a gradeor slope, of even 30 angularity such as is commonly found in conveyorinstallations of the type in quetsion. In this case, a low suspensionofxthe hanger on the. trolley is likely to cause the line of vertical orgravitational action of a hanger and its load to fall forwardly of agravitational, vertical load componenton the forward trolley'roller 17,acting through its axle or axis 34. Under this situation, the verticaldownward load. moment'of the hanger about the axis. of. the forward.roller combines with the forward force couple of the power conveyor dog23 on the forward trolley dog 32 about the same axis, and forwardtilting or. up-ending is apt to occur, requiring the use of specialhold-down means to restrain the trolley vertically.

Referring to Fig. 2 of the drawings, the reference numeral 49 generallydesignates a horizontal transfer chain which is mounted adjacent theswitch mechanism 11, as shown in my copending application. This chain islocated inwardly of the main track sections 12, 12 and the branch tracksection 14, being trained to traverse a generally triangular thoughrounded path. The transfer chain 40 is driven in a caterpillar fashionfrom the main trolley advancing chain 27; and to this end chain 40 is.provided with a series of laterally outwardly extending,

driving dog units 41. Each such unit comprises a lug or dog 42 welded toa link of the chain 40 and having driving engagement with main chain'27,and a downwardly spaced, outwardly extendingtrolley engaging and for-.warding dog or lug 43, the lug.43 being of somewhat.

greater length, in.the lateral sense, than the dog 42.

2), and as it extends in the direction of branch track section 14, theguide 44 is angled away from that section, for the purpose of graduallydisengaging the trolley advancing lugs 43 of chain 40 from the trolleysengaged and driven thereby in effecting the transfer movement throughswitch 11. Main driving chain 27 may be backed by vertically journaledrollers 45.

Thus it is seen that the dogs 42 of transfer chain 40 engage the maindrive chain 27 to derive power, and that the transfer chain lugs 43 comeinto position between the trolley dogs 31, 32 to push the trolleythrough the switch 11 in the open position thereof shown in dotted linein Fig. 4. Departing from the switch zone onto the branch track, theleading guide roller 21 of the driven trolley engages the reset arm ofswitch unit 11 to restore its tongue 20 to normal solid line position,for a straight-through travel of further trolleys along main tracksections 12, 12'.

Simple mathematical computations establish the fact that, with the axis28 of hinged suspension of the load located as high as is practicallypossible between forward and rearward load rollers 17, and when thetrolley is propelled up a slope, the line of gravitational load on thetrolley itself is brought between front and rear resultants of thedownward component of (a) a force-couple exerted upon the forwardtrolley dog (the moment arm of which is the distance between the dog anda plane through the axes of the forward and rear rollers), combined with(1;) components of trolley-on-track load effect on the forward andrearward rollers. Hence, regardless of slope (within reasonable limits),there will never be any tendency of the trolley, occasioned by an upwardresultant at the rear roller, to tilt or up-end forwardly about itsforward roller axis, hence requiring hold-down provisions to hold therearward roller in contact with the track.

What I claim as my invention is:

1. A traveling work supporting unit comprising a carriage provided withforward and rearward load bearing rollers journaled on parallel axes andadapted to roll on a track, a dog connected with said carriage fordriving the carriage, said dog projecting upwardly in relation to saidforward and rearward roller axes and between the same for forwarddriving engagement above said axes by a power member acting in aforce-couple about the forward axis, and means for pivotally suspendinga load supporting hanger on said carriage on an axis between saidforward and rearward roller axes and in sufliciently closely adjacentvertical relation to and below a plane through said roller axes to atall times, regardless of the slope of travel of said unit, maintain thegravitational action of said hanger and its load on a line betweendownward components of combined load action on said forward and rearwardload rollers and force-couple action of said power member about saidforward axis, thereby to prevent up-ending of said rearward rollers fromsaid track, as in ascending a slope.

2. A traveling work supporting unit comprising a carriage provided withpairs of forward and rearward load bearing rollers journalled onparallel axes and each including rollers transversely spaced in thedirection of their axes and adapted to roll on laterally spacedhorizontal track members, a dog connected with said carriage for drivingthe carriage, said dog projecting upwardly in relation to said forwardand rearward roller axes and between the same for forward drivingengagement above said axes by a power member acting in a force-coupleabout the forward axis, means for pivotally suspending a load supportinghanger on said carriage on an axis between said forward and rearwardroller axes, said last named axis being located in sufficiently closelyadjacent vertical relation to a plane through said roller axes to at alltimes, regardless of the slope of travel of said unit, maintain thegravitational action of said hanger and its load on a line betweendownward components of combined load action on said forward and rearwardroller axes and force-couple action of said power member about saidforward axis, thereby to prevent up-ending of said rearward roller fromsaid track, as in ascending a slope, and a pair of forward and rearward,vertically journalled guide rollers located on said carriage adjacentthe rollers of said respective forward and rearward pairs and adapted tobe guided between vertical portions of said track members.

References Cited in the file of this patent UNITED STATES PATENTS1,312,417 Mosher Aug. 5, 1919 1,443,382 Rapier Jan. 30, 1923 1,690,502Raymond Nov. 6, 1928 1,850,048 Ballew Mar. 15, 1932 2,485,215 Rose Oct.18, 1949 2,868,138 Bishop et a1. Jan. 13, 1959 2,868,139 Klamp Jan. 13,1959 2,875,703 Bishop et a1. Mar. 3, 1959

